FIG. 1 is an exploded view of a conventional ratchet wrench. The ratchet wrench comprises a main body 200, a ratchet wheel 210, a detent 220, and a switch knob 230. The main body 200 has a first accommodation trough 201, a second accommodation trough 202, and a third accommodation trough 203. The ratchet wheel 210 is disposed in the first accommodation trough 201. The outer peripheral wall of the ratchet wheel 210 is provided with a toothed portion 211. The detent 220 is disposed in the second accommodation trough 202. One side of the detent 220 is provided with meshing teeth 221. The meshing teeth 221 are adapted to mesh with the toothed portion 211. The switch knob 230 is disposed in the third accommodation trough 203. The switch knob 230 is provided with a lever 231 and an elastic member 232. When the switch knob 230 is turned in the third accommodation trough 203 of the main body 200, the switch knob 230 drives the elastic member 232 to turn at an angle. The elastic member 232 urges the detent 22 to offset in the second accommodation trough 202, so that the ratchet wrench can be switched for a forward rotation or a reverse rotation to facilitate the user's operation.
However, the conventional ratchet wrench has a complicated structure, and its reversing device is small in size and difficult to assemble and position. The switch knob 230 is connected with the exposed lever 232 by riveting. The user can switch the switch knob 230 to change the direction of turning. The conventional ratchet wrench has too many parts, and the assembly of the parts is extremely complicated. When the user wants to perform a reversing operation, the user usually holds the main body 200 with one hand and turns the switch knob 230 with the other hand. The reversing operation cannot be implemented with one hand only. The conventional ratchet wrench increases the production cost and working hours. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.